Tuesday, July 7, 2009

Sweat rate

I did the experiment to calculate my sweat rate last night. A hot run in the evening, though not as hot as the specialty run, which I skipped because I didn't want to melt and then expire. So I did a quick 30 minute tempo run around the neighborhood, keeping my heart rate above 140. And back at home, I was 1 lb less, which works out to 2 lbs, or 32 ounces, or 0.9 L per hour. And they suggest you divide by 4 to get what you should drink every 15 minutes- so most easily that is 8 oz or about 1/2 of a small water bottle. That is a lot, but if I'm sweating that much out, then it's important to replace.

The other part I learned today is that with every pound of water loss, the heart rate increases about 4-8 beats per minute at the same performance effort. So you feel like you're working harder, but you're not going any faster. Very interesting.

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